Six killed in Kabul explosions after Obama visit

At least six people were killed as explosions and gunfire rattled a major foreign guesthouse complex in Kabul on Wednesday, just hours after a surprise overnight visit by US President Barack Obama, AFP reports.

Smoke was seen emanating from the high security "Green Village", used by UN and European Union staff, near the Afghan capital's main airport which was earlier rocked by a suicide car bomb attack that was claimed by Taliban insurgents.

The assault on the first anniversary of the death of Osama bin Laden came two weeks after Kabul was hit by its biggest attacks in 10 years of war, which saw squads of militants target government offices, embassies and foreign bases.

The US embassy immediately sounded alarm following Wednesday's attack, saying its embassy was "under lockdown" and warned staff to "take cover, move away from the windows".

"Duck and cover here at the embassy. Not a drill - avoid the area," the US embassy said on Twitter.

Obama earlier dropped from night skies into Kabul on a brief visit amid secrecy and tight security and signed a deal with President Hamid Karzai, cementing 10 years of US aid for Afghanistan after NATO combat troops leave in 2014.

The attacks are a reminder of the extremist threat that stalks Afghanistan, with the Taliban resurgent a decade after they were driven from power for refusing to hand over bin Laden following the 9/11 attacks.

"Five civilians and one guard were killed," said interior ministry spokesman Sediq Sediqqi, adding that the target was the "Green Village" used by international organisations.

The Taliban claimed responsibility for the suicide attack.

"Today a devoted mujahid carried out a suicide car bomb attack on a foreign military base in Kabul, followed by other devoted mujahids (holy warriors) entering the base," a Taliban spokesman told AFP.

Karzai said the US pact "is not threatening any third country, including the neighbouring countries, but we are hoping that this leads to stability, prosperity and development in the region".

"Neither Americans nor the Afghan people asked for this war, yet for a decade we've stood together," Obama said at the signing ceremony.

"We look forward to a future of peace. We're agreeing to be long-term partners," said Obama, who later headed home aboard Air Force One after just six hours on the ground.

The pact, agreed last month, sees the possibility of American forces staying behind to train Afghan forces and pursue the remnants of Al-Qaeda for 10 years after 2014.

It does not commit Washington to specific troop or funding levels for Afghanistan, though it is meant to signal that despite ending the longest war in US history, Washington intends to ensure Afghanistan does not revert to a haven for terror groups like Al-Qaeda.

But after a war that has cost the lives of nearly 3,000 US and allied troops, maimed tens of thousands more, saw thousands of Afghans killed and cost hundreds of billions of dollars, Afghanistan's future remains deeply uncertain.